Anode construction



May 25, 1948. c. v. LITTON 2,441,971

` ANoDE CONSTRUCTION Y Filed De. 4, 1944 2 Sheets-Sheet 1 INVENTVOR CHARLES V. L rrroN BY A i ATTORNEY May 25, v1948. c. v. LrrToN ANODE CONSTRUCTION n Filed Deo. 4, 1944 2 Sheets-Sheet 2 INVENTOR CHARLES V.LITTON ATTORNEY um and the Patented May 25, 1948 Charles V. Litton,

to Federal Telephone and Redwood City, Calif., assgnor Radio Corporation,

New York, N. Y., a corporation of Delaware Application December 4, 1944, Serial No. 566,449

14 claims. (ol. 25o-27.5)

This invention relates to electronv discharge I tubes and particularly to an anode construction for a high power therm-ionic tube, such as is used for the output stage of a carrier wave transmitter.

In high powered therminoic tubes, it is often desirable to provide and thus prevent it from overheating during the operation of the tube, and when suchV cooling means is used, it is preferable to provide a good heat conducting path between the cooling medianode and a long enough one so as to provide a suflicient heat gradient between the anode and cooling medium to prevent overheating of the medium. The anode however is subj ect to expansion upon the temperature being 'raised and, when fluid cooling meansis used, it is dini cult to provide the conducting path betweenthe cooling medium and the anode'and at the saine time permit the anode to expand freely with temperature changes to prevent f's'tructura'lstrains from deteriorating the anode wall.

It is one of the objects of the present invention to'provide an anode structure for a thermionic tube having a fluid cooling means which has a good heat conducting path between the cooling medium and the anode and at the Sametime will permit expansion of the anode with temperature changes.

Another object of the invention is to provide an anode structure for a thermionic tube having a fluid cooling means Whichis connected to the anode structure bya good heat conductingpath but which is free to` expand axially of the anode structure when the anode structure expands axially thereof so as to permit the anode structure to expand freely with temperature changes. i

Another object of the inventionis to provide an anode structure for a thermionic tube having a fluid cooling means in the form of a coiled tubular uid conductor with separate heat conducting paths between the turns of the tubular uid conductor and the anode structurey to permit the turns of the iiuid` conductor-to separate when the anode structure expands axiallythere-v of. Other objects of the invention willfbe apparent as the description thereof proceeds."

Several embodiments of the invention vhave some means to cool the .anode 25 provided which been illustrated in the accompanying drawings, in which: Fig. 1 is a side elevational view, partly in section, of an anode structure incorporating one form of the invention;

Fig. 2 is a fragmentary sectional elevational view through the side wall of the anode structure of Fig. 1 illustratingv the manner in which expansion takes place in the anode and the effect of such expansion on the cooling means;

Fig. 3 is an elevational View partly in section of the embodiment shown in Fig. 1 showing the parts in their expanded form;

Fig. 4 is a sectional elevational view of a slightly diierent form of the invention from that shown in Fig. 1 with a larger number of heat conducting rings than there are fluid conducting coils; y

Fig. 5 is aside elevational view of a modied formof the fluid conducting coils shown in Figs. 1, 2 and 3;

Y Fig.l 6 isa sectional elevational View oi a modied form of the invention in which, instead of heat conducting rings, a single spiral member is has substantiallythe same cross section as the rings.

' In Fig. 1 is shown one form ofthe invention which may be preferred because of its simplicity and ease of manufacture. A high power thermionic tube I, such as a transmitting tube, is shown provided with a conventional cathode and grid structure 2, indicated in dot and dash lines, and a heavy tubular anode 3 which forms the outer shell of the tube and which is sealed into a glass envelope 4 which insulates it from the supports for the other elements.

The anode 3 is circular in cross section and around it are placed a plurality of heat conducting'members such as flat rings 5 of copper or other good heat conducting metal, and these rings have their inner surfaces welded or otherwise attached to the anode 3 as indicated at 6' in Figs. -1 and 2, so as to provide good heat conductivity between the inner surface ofthe rings and the outer surface of the anode structure.v The rings are preferably placed close together in order to increase the mass of the anode and provide a greater heat conducting path from the anode to the outer surfaces of the rings.

, In close contact with the outer surfaces of the rings I provide a duct or ducts 'l for circulating cooling uid. These ducts may take the form of a coil of metal tubing, as, for instance, copper, which is provided WithV suitable inlet and outlet fittings, (not shown), so that Water or other cooling medium may be introduced into the inlet 8 at the top and be brought out of the outlet 9 at the bottom. The inside surfaces of the turns of the coil 'l are preferably Welded to the outer sur-V faces of the rings 5, as indicated at Edin Figs. l and 2 and by the shaded areas in Fig. 3.

In the embodiments shown in Figs. 1 to 3 the fluid conducting .duct has the saine verticalV dimension per .turn as the vertical dimension of the ring and there is one turn of the fluidcon-U ducting duct per ring. Since the fluid conductor is in the form of a coil the turns of theduct-.do

not exactly align With the rings and Vthere is a cross over from one ring to the nektladjaqent ring. Each turn of the duct therefore is virelde1di to a particular ring for the majorY distance fofthe turn, but as the duct crosses-over the-oracle Ybetween two adjacent rings itis leftunivelded i Thus, in Fig. 3 each with respect to both rings. turn 1 is Welded to its associated ring for a distance around the f circuinferer'iceV extendingv around the opposite side of the assembly between the dot and dashlines 'l land fl 2; Between 4vthese lines "on" the lforward `side of the assembly. the ducts are not Welded to the'frings.' 'l2i1erefore', although the Welded portion nof'eech turn ofthe ductma'y not bencLthe 'unweldedv portionof each turn-may `bend slightly asthe anode expands axiiallyitoperm'it the separation of the 'turn-s of the duct, as indicated inFig. 3. Y

The' temperature 'of the` inner surface ofeach ring will Abeapfproximately the-*same-as the outer surface of the anodestructure and hence will exe pand" the same V`amount yas the anode if the two materials are `the same., The metal ofreachring is cooler as 'it .approaches the outer .surface where it is Tin contact with'the cooling Vduct 4and hence will expand less and less in the axial direction of 'the anode as it lapproaches the outer surface. Therefore, the crosss'ection of Veach ringwhen under operating conditions will assumerthe shape as is rshoWn .in the exaggerated form in Fig; 2 and the separate turns of 'theduct 'l will separate,

as indicated.

While it maybe .preferable to yhave 'the ducts '50 with the same dimension axiallyof the anode-.as the rings, this is not necessary, as larger ducts may be' used if desired, as indicated in Fig. .4. Here; the `duct I3 has a'greater vertical dimension than each.' ring At and ,consequently there are fewer turns of the duct than there are ringsi The welding of theV turns of the duct to the rings is accomplished A.as described before, eachV iturnY being welded to the major portion of'onering, Vand then a space is left correspondingto the 'space between the dot and dash lines Il and l-Eof Fig. 3 VWhere the duct is not Welded to'any ring. At this un-V welded portion the duct may bend slightly so as to permit Vseparationof the turns of the-duct I3 as the anode expands andthe outer e'd'gesfof. the rings separate.` This same principal' of welding the duct ofthe rings is followed if the turns'of the duct `are spaced "apart so Vas jtof increase the pitchzof the spiral.` Y InV some instances it maybedesirableto provide the duct, as shown in"Fig. 5,Witha Lmajor portion `of each turn lying in thesam'e plane-as the Vring and `having an loifset portion i'which joins one turn of the ductjv'vith the 'nextadjacent turn. Jl/'here this arrangement of duct is used 65 'of said ring members.

With rings having the same dimension in the axial direction of the anode as the duct, the major portion I4 of each turn of the duct may be exactly aligned with the ring and welded to the entire 5 outer surface of the ring, thus making a better heat rconducting joint. Where there arefewer turns of the duct than the number of rings or Where the duct is provided in a true spiral, as in Figs. 1 to 3, it will not be possible to Weld the entire outer surface of each ring to one of the turns of the duct, since the pitch of the duct coil necessitates an overlapping of ringsand ducts.

The 'most practical Way of making the heat conducting members is in the form of the rings, as

` shown in Figs; 1 to 5 inclusive. However, it may be desired to make the heat conducting members of j -a-Vsingleapiece of metal having the cross section ofa ringfof the previous figures and wound in a :spiral 1f6, as s h'ovvn 'in Fig. 6. VWith such an arorangernentthelimension in the axial direction of theanodeofboth spiral heat conducting members i f lesa-nd duct J may be the same and the pitch may v be thebsam'e, so that the outer surface of the heat conducting spiral It may be Welded to the inner surface of the duct l throughout the entire length of both. "'-Thi's'will `.providean excellent hea-t conductingcontact betweenthetwo and at 'the same time the turns ofthe coil may separateas the anode expands. Y 1

It will be seen from the above that I have provided a simple an'odestructure by means of which agood heat conducting-path is 'provided between the anode andthe cooling medium therefore, 'while at the `same time movement of the' anode caused by-expansionunder increased temperature' is permitted' Without disturbing the heat conducting path. VStrainswvill` therefore be prevented from being setup in the anode "which 'tend to cause structural deterioration after the anode has been 40 in operation'ror a period of time. Various modifications on fthe invention will sug-Y gestV themselves to'those skilled in the art, yand I thereforev zdo' notdesireV toY limit my invention exceptby thelimitations defined in the appended What is claimed iszff 1. YVAn anodestruct'ure for an electrondiseharge tubecomprising -atubular anode member, a plurality'of closely positioned heat conducting ring Vmembers'.extending around `the 4outside of said tubular anode .member with the inner surfaces of said heat conduotingmembers in heat conducting contact with the outer surface of` lsaid member,

f said heat conductingring members having-a substantially rectangular cross-section -With the lesser dimension along the .axis of said :anode member,

Y said ring members Ybeing placed inA -contactat their inner peripheries,.and fluid coolingme'ans in the form of, a "coil in heat conducting contact with the'outer` surfaces ofV said heat-conducting ring members, said fluidV cooling meansbeing secured to said ring membersfor only@d portion of each turn of said fluid cooling means forallowingaxial expansion of said anode member `and,separation 2. An anode structure for'an electron discharge tube comprising a tubularfanode memberfaplurality of 5 closely positioned heat conducting Vring Vmembers surrounding 'said tubulark anode memberV with Vthe inner surfaces of said heat conducting rnembersv welded tofsaid anodeV member, said heat conducting ring members having fa substantiallyfrectangular cross-section Withthe lesser dimension extending .axially Yof said anode niem- V ber,said ring members being placed in contact at their inner peripheries, and fluid cooling means in the form of a coil in heat conducting contact with the outer surfaces of said heat conducting ring memberssaid fluid cooling means being secured to said ring members for only a portion of each turn of said fluid cooling means for permitting axial-'expansion of said anode member and separation of said ring members.

3. An anode structure for an electron discharge tube comprising a tubular anode member, a plurality of heat conducting ring members surrounding said anode member with the inner surfaces of said heat condu-cting members in heat conducting contact with the outer surface of said anode member, said heat conducting members having a substantially rectangular cross-section With the lesser dimension in the axial direction of said anode member, said ring members being placed in contact with each other at their inner peripheries, and a duct through which cooling fluid is adapted to be circulated arranged in a coil in close heat conducting contact with the outer surfaces of said heat conducting members, said duct being secured to said ring members for only a portion of each turn of said duct for allowing axial expansion of said anode and separation of said ring I members.

4. An anode structure for an electron discharge tube in accordance with lclaim 3, in which each individual turn of the duct for circulating the cooling iiuid is attached to a separate one of said heat conducting members.

5. An anode structure for an electron discharge tube in accordancewith claim 3, in which each individual turn of the duct for circulating the cooling fluid is Welded to the outer surface of a separate one of said heat conducting-members.

6. An anode structure for an electron discharge tube comprising a tubular anode member, a plurality of heat conducting members surrounding said anode member with the inner surfaces of said heat conducting members attached in heat conducting relation with the outer surface of said anode member, said heat conducting members having a substantially rectangular cross-section with the lesser dimension in the axial direction of said anode member, said heat conducting members being placed in contact with each other at their internal peripheries, a metal duct through which a cooling fluid is adapted to -be circulated arranged in a coil surrounding said heat conducting members, each turn of said coil being Welded throughout the major portion of the distance around said heat conducting members to a separate heat conducting member, there being a suicient length of duct left unwelded in each turn at a point where said duct crosses over from one heat conducting member to another to permit bending of the unwelded portion of said duct, so as to permit the turns of the coil of said duct to separate as said anode member expands in an axial direction.

7. An anode structure for a thermionic tube comprising a tubular metal member, a plurality of metal rings surrounding said tubular moember with the inner surfaces of said rings welded to the outer surface of said member, said metal rings being arranged in contact with each other at their internal peripheries, and a coil of metal tubing adapted to conduct cooling fluid surrounding said rings and having its inner surface welded to the outer surfaces of said rings, each turn of said coil being welded to one of said metal rings for only a portion of said turn for permitting axial expan- 6 sion of said tubular metal member and separation of said metal rings.

8. An anode structure for a thermionic tube comprising a tubular metal member having a circular cross-section, a plurality of metal ringssu1' rounding said tubular member with the inner surfaces of said rings welded to the outer surface of said member, said rings being arranged in `contact with each other at their inner peripheries, and a -coil of metal tubing adapted to conduct cooling fluid surrounding said rings and having its inner surface Welded to the outer surfaces of said rings, each turn of said coil of metal tubing being Welded to one of said rings for only a portion of said turn for permitting bending of the unWelded portion of each turn of said coil with axial expansion of said metal member.

9. An anode structure for a thermionic tube comprising a tubular member of copper having a circular cross-section, a plurality of closely positioned, at, copper rings surrounding said tubular member with the inner surfaces of said rings welded to the outer surface of said member, said copper rings being arranged in contact With each other at their inner peripheries, and a coil of metal tubing adapted to conduct cooling uid surrounding said rings and having its inner surface Welded to the outer surfaces of said rings, each turn of said coil of metal tubing being Welded to one of said copper rings for only a portion of said turn for permitting bending of the unwelded portion of each turn of said coil with axial expansion of said tubular member.

10. An anode structure for an electron discharge tube comprising a tubular metal anode member, a plurality of heat conducting members surrounding said tubular anode member with the inner surfaces of said heat conducting members welded to the outer surface of said member, and a coil of metal tubing adapted to conduct cooling uid surrounding said heat conducting members, said coil being Wound with each turn in a flat plane perpendicular to the axis of the coil throughout a major portion of the turn and with the remaining portion of each turn bent at an angle to said plane to connect with the next adjacent turn, the major portion of each turn which lies in said plane being welded to a separate one of said members with the remaining portion of ea-ch turn left unwelded.

ll. An anode structure for a thermionic tube according to claim 10, in which the heat conducting members are metal rings and one is provided for each turn of the fluid conducting tubing.

12. An anode structure for a thermionic tube in accordance With claim l0, in which the anode member has a -circular cross-esection and the heat conducting members are metal rings and there is one turn of the tubing for the cooling fluid for each of said rings.

13. An anode structure for an electron discharge tube comprising a tubular anode member, aplurality of heat conducting members surrounding said anode member with the inner surfaces of said heat conducting members in heat conducting contact with the outer surface of said anode member, said heat conducting members being formed of a single bar surrounding said anode member in a helix, said bar being secured to said anode member for only a portion of each turn of said bar, and a duct through which cooling fluid is adapted to be circulated arranged in a coil in close heat conducting contact with the outer surfaces of said heat conducting members whereby 2, 47419f71 7.. the, unweldedportion of said, barmzuy bend withv axial expansion of said tubular anode menroel';

FOREIGN E PATENTS REFERENCES CITED l()4 Y Y Number Country Date The following references are of record in the 514,651 Great-Britain ;May 12,1938 le of this patent; 555,323

Great Britain Feb. 10,V 1942 

